Anyone can develop an allergy to insect stings, but people with other allergies or allergic diseases like asthma are more likely to have severe anaphylaxis if they become allergic to venom.

Which insects cause allergic reactions?

There are three families of insects that cause the most allergies. These are:

• vespids (Vespidae): yellow jackets, hornets, wasps
• bees (Apidae): honey bees, bumblebees (occasionally), sweat bees (infrequent)
• ants (Formicidae): fire ants (commonly cause anaphylaxis), harvester ants (less common cause of anaphylaxis)

Wasps, hornets and bees are the most common source of allergic reactions worldwide, with a third of patients treated for anaphylaxis having symptoms triggered by stings, mostly bee stings. Less severe reactions include extensive swelling (angioedema), itching, nettle rash (urticaria), pain and redness.

Rarely, bites from the following insects may cause anaphylaxis:

• mosquitoes
• bed bugs
• kissing bugs
• deer flies

 Midges and Mosquitoes

It used to be thought that allergy to the bites of midges and mosquitoes was rare and that allergic reactions were due to inhaled particles from them, causing allergic symptoms in the nose and lungs.

But recent research at the University of Manitoba in Canada has identified what has been dubbed 'skeeter syndrome', a very large swelling around the area of the bite accompanied by fever. Skeeter syndrome is seen most often in young children and those with lowered immunity. There have also been reports of asthmatics suffering asthma attacks in response to mosquito bites.

People with dermatographism - where the skin reacts with wheals that look like scribbles on the skin - often show an unusually large local reaction to mosquito bites but this is largely due to the general sensitivity of their skin.

Venom allergy

Not all snake bites are fatal and some snakes, such as the adder, deliver a bite that many people survive. But others, who have developed an allergic reaction, do not, anaphylactic shock coming on top of the symptoms caused by the toxins in the venom.

Treatment

Avoidance is critical for those at risk.

More allergy information and advice here